Preheat oven to 190°C
Scatter tomatoes and dry lentils over bottom of a 25x25-cm baking dish.
Add garlic, lay sausages over the top, and pour stock over everything.
Drizzle with balsamic vinegar and oil. Toss in a few sprigs of thyme or rosemary, and sprinkle with salt and pepper. Poke each sausage once or twice with a fork.
Bake uncovered for 40-45 minutes, until sausages are golden and cooked through and lentils are tender. Let stand for a few minutes before serving. Serve with crusty bread for mopping up the juices.